GitNews Web - Trending repositories from GitHub, HackerNews & Reddit
SmallDevTools - Handy developer tools with a delightful interface
LibHunt - LibHunt tracks mentions of software libraries on relevant social networks. Based on that data, you can find the most popular projects and their alternatives.
Google Open Source - All of Googles open source projects under a single umbrella
AlternativeTo - AlternativeTo lets you find apps and software for Windows, Mac, Linux, iPhone, iPad, Android, Android Tablets, Web Apps, Online, Windows Tablets and more by recommending alternatives to apps you already know.
whatdevsneed - This is whatdevsneed.